Methods and apparatus for processing audio signals

ABSTRACT

Various methods and apparatus for processing audio signals are disclosed herein. The assembly may be attached, adhered, or otherwise embedded into or upon a removable oral appliance to form a hearing aid assembly. Such an oral appliance may be a custom-made device which can enhance and/or optimize received audio signals for vibrational conduction to the user. Received audio signals may be processed to cancel acoustic echo such that undesired sounds received by one or more intra-buccal and/or extra-buccal microphones are eliminated or mitigated. Additionally, a multiband actuation system may be used where two or more transducers each deliver sounds within certain frequencies. Also, the assembly may also utilize the sensation of directionality via the conducted vibrations to emulate directional perception of audio signals received by the user. Another feature may include the ability to vibrationally conduct ancillary audio signals to the user along with primary audio signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/261,759 filed Apr. 25, 2014, which is a continuation of U.S. patentapplication Ser. No. 12/840,213 filed Jul. 20, 2010 (now U.S. Pat. No.8,712,077 issued Apr. 29, 2014), which is a continuation of U.S. patentapplication Ser. No. 11/672,250 filed Feb. 7, 2007 (now U.S. Pat. No.7,844,070 issued Nov. 30, 2010), which claims the benefit of priority toU.S. Provisional Patent Application Nos. 60/809,244 filed May 30, 2006and 60/820,223 filed Jul. 24, 2006, each of which are incorporatedherein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to methods and apparatus for processingand/or enhancing audio signals for transmitting these signals asvibrations through teeth or bone structures in and/or around a mouth.More particularly, the present invention relates to methods andapparatus for receiving audio signals and processing them to enhance itsquality and/or to emulate various auditory features for transmittingthese signals via sound conduction through teeth or bone structures inand/or around the mouth such that the transmitted signals correlate toauditory signals received by a user.

BACKGROUND OF THE INVENTION

Hearing loss affects over 31 million people in the United States (about13% of the population). As a chronic condition, the incidence of hearingimpairment rivals that of heart disease and, like heart disease, theincidence of hearing impairment increases sharply with age.

While the vast majority of those with hearing loss can be helped by awell-fitted, high quality hearing device, only 22% of the total hearingimpaired population own hearing devices. Current products anddistribution methods are not able to satisfy or reach over 20 millionpersons with hearing impairment in the U.S. alone.

Hearing loss adversely affects a person's quality of life andpsychological well-being. Individuals with hearing impairment oftenwithdraw from social interactions to avoid frustrations resulting frominability to understand conversations. Recent studies have shown thathearing impairment causes increased stress levels, reducedself-confidence, reduced sociability and reduced effectiveness in theworkplace.

The human ear generally comprises three regions: the outer ear, themiddle ear, and the inner ear. The outer ear generally comprises theexternal auricle and the ear canal, which is a tubular pathway throughwhich sound reaches the middle ear. The outer ear is separated from themiddle ear by the tympanic membrane (eardrum). The middle ear generallycomprises three small bones, known as the ossicles, which form amechanical conductor from the tympanic membrane to the inner ear.Finally, the inner ear includes the cochlea, which is a fluid-filledstructure that contains a large number of delicate sensory hair cellsthat are connected to the auditory nerve.

Hearing loss can also be classified in terms of being conductive,sensorineural, or a combination of both. Conductive hearing impairmenttypically results from diseases or disorders that limit the transmissionof sound through the middle ear. Most conductive impairments can betreated medically or surgically. Purely conductive hearing lossrepresents a relatively small portion of the total hearing impairedpopulation (estimated at less than 5% of the total hearing impairedpopulation).

Sensorineural hearing losses occur mostly in the inner ear and accountfor the vast majority of hearing impairment (estimated at 90-95% of thetotal hearing impaired population). Sensorineural hearing impairment(sometimes called “nerve loss”) is largely caused by damage to thesensory hair cells inside the cochlea. Sensorineural hearing impairmentoccurs naturally as a result of aging or prolonged exposure to loudmusic and noise. This type of hearing loss cannot be reversed nor can itbe medically or surgically treated; however, the use of properly fittedhearing devices can improve the individual's quality of life.

Conventional hearing devices are the most common devices used to treatmild to severe sensorineural hearing impairment. These are acousticdevices that amplify sound to the tympanic membrane. These devices areindividually customizable to the patient's physical and acousticalcharacteristics over four to six separate visits to an audiologist orhearing instrument specialist. Such devices generally comprise amicrophone, amplifier, battery, and speaker. Recently, hearing devicemanufacturers have increased the sophistication of sound processing,often using digital technology, to provide features such asprogrammability and multi-band compression. Although these devices havebeen miniaturized and are less obtrusive, they are still visible andhave major acoustic limitation.

Industry research has shown that the primary obstacles for notpurchasing a hearing device generally include: a) the stigma associatedwith wearing a hearing device; b) dissenting attitudes on the part ofthe medical profession, particularly ENT physicians; c) product valueissues related to perceived performance problems; d) general lack ofinformation and education at the consumer and physician level; and e)negative word-of-mouth from dissatisfied users.

Other devices such as cochlear implants have been developed for peoplewho have severe to profound hearing loss and are essentially deaf(approximately 2% of the total hearing impaired population). Theelectrode of a cochlear implant is inserted into the inner ear in aninvasive and non-reversible surgery. The electrode electricallystimulates the auditory nerve through an electrode array that providesaudible cues to the user, which are not usually interpreted by the brainas normal sound. Users generally require intensive and extendedcounseling and training following surgery to achieve the expectedbenefit.

Other devices such as electronic middle ear implants generally aresurgically placed within the middle ear of the hearing impaired. Theyare surgically implanted devices with an externally worn component.

The manufacture, fitting and dispensing of hearing devices remain anarcane and inefficient process. Most hearing devices are custommanufactured, fabricated by the manufacturer to fit the ear of eachprospective purchaser. An impression of the ear canal is taken by thedispenser (either an audiologist or licensed hearing instrumentspecialist) and mailed to the manufacturer for interpretation andfabrication of the custom molded rigid plastic casing. Hand-wiredelectronics and transducers (microphone and speaker) are then placedinside the casing, and the final product is shipped back to thedispensing professional after some period of time, typically one to twoweeks.

The time cycle for dispensing a hearing device, from the firstdiagnostic session to the final fine-tuning session, typically spans aperiod over several weeks, such as six to eight weeks, and involvesmultiple with the dispenser.

Moreover, typical hearing aid devices fail to eliminate backgroundnoises or fail to distinguish between background noise and desiredsounds. Accordingly, there exists a need for methods and apparatus forreceiving audio signals and processing them to enhance its qualityand/or to emulate various auditory features for transmitting thesesignals via sound conduction through teeth or bone structures in and/oraround the mouth for facilitating the treatment of hearing loss inpatients.

SUMMARY OF THE INVENTION

An electronic and transducer device may be attached, adhered, orotherwise embedded into or upon a removable dental or oral appliance toform a hearing aid assembly. Such a removable oral appliance may be acustom-made device fabricated from a thermal forming process utilizing areplicate model of a dental structure obtained by conventional dentalimpression methods. The electronic and transducer assembly may receiveincoming sounds either directly or through a receiver to process andamplify the signals and transmit the processed sounds via a vibratingtransducer element coupled to a tooth or other bone structure, such asthe maxillary, mandibular, or palatine bone structure.

The assembly for transmitting vibrations via at least one tooth maygenerally comprise a housing having a shape which is conformable to atleast a portion of the at least one tooth, and an actuatable transducerdisposed within or upon the housing and in vibratory communication witha surface of the at least one tooth. Moreover, the transducer itself maybe a separate assembly from the electronics and may be positioned alonganother surface of the tooth, such as the occlusal surface, or evenattached to an implanted post or screw embedded into the underlyingbone.

In receiving and processing the various audio signals typically receivedby a user, various configurations of the oral appliance and processingof the received audio signals may be utilized to enhance and/or optimizethe conducted vibrations which are transmitted to the user. Forinstance, in configurations where one or more microphones are positionedwithin the user's mouth, filtering features such as Acoustic EchoCancellation (AEC) may be optionally utilized to eliminate or mitigateundesired sounds received by the microphones. In such a configuration,at least two intra-buccal microphones may be utilized to separate outdesired sounds (e.g., sounds received from outside the body such asspeech, music, etc.) from undesirable sounds (e.g., sounds resultingfrom chewing, swallowing, breathing, self-speech, teeth grinding, etc.).

If these undesirable sounds are not filtered or cancelled, they may beamplified along with the desired audio signals making for potentiallyunintelligible audio quality for the user. Additionally, desired audiosounds may be generally received at relatively lower sound pressurelevels because such signals are more likely to be generated at adistance from the user and may have to pass through the cheek of theuser while the undesired sounds are more likely to be generated locallywithin the oral cavity of the user. Samples of the undesired sounds maybe compared against desired sounds to eliminate or mitigate theundesired sounds prior to actuating the one or more transducers tovibrate only the resulting desired sounds to the user.

Independent from or in combination with acoustic echo cancellation,another processing feature for the oral appliance may include use of amultiband actuation system to facilitate the efficiency with which audiosignals may be conducted to the user. Rather than utilizing a singletransducer to cover the entire range of the frequency spectrum (e.g.,200 Hz to 10,000 Hz), one variation may utilize two or more transducerswhere each transducer is utilized to deliver sounds within certainfrequencies. For instance, a first transducer may be utilized to deliversounds in the 200 Hz to 2000 Hz frequency range and a second transducermay be used to deliver sounds in the 2000 Hz to 10,000 Hz frequencyrange. Alternatively, these frequency ranges may be discrete oroverlapping. As individual transducers may be configured to handle onlya subset of the frequency spectrum, the transducers may be moreefficient in their design.

Yet another process which may utilize the multiple transducers mayinclude the utilization of directionality via the conducted vibrationsto emulate the directional perception of audio signals received by theuser. In one example for providing the perception of directionality withan oral appliance, two or more transducers may be positioned apart fromone another along respective retaining portions. One transducer may beactuated corresponding to an audio signal while the other transducer maybe actuated corresponding to the same audio signal but with a phaseand/or amplitude and/or delay difference intentionally inducedcorresponding to a direction emulated for the user. Generally, uponreceiving a directional audio signal and depending upon the direction tobe emulated and the separation between the respective transducers, aparticular phase and/or gain and/or delay change to the audio signal maybe applied to the respective transducer while leaving the othertransducer to receive the audio signal unchanged.

Another feature which may utilize the oral appliance and processingcapabilities may include the ability to vibrationally conduct ancillaryaudio signals to the user, e.g., the oral appliance may be configured towirelessly receive and conduct signals from secondary audio sources tothe user. Examples may include the transmission of an alarm signal whichonly the user may hear or music conducted to the user in publiclocations, etc. The user may thus enjoy privacy in receiving theseancillary signals while also being able to listen and/or converse in anenvironment where a primary audio signal is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the dentition of a patient's teeth and one variationof a hearing aid device which is removably placed upon or against thepatient's tooth or teeth as a removable oral appliance.

FIG. 2A illustrates a perspective view of the lower teeth showing oneexemplary location for placement of the removable oral appliance hearingaid device.

FIG. 2B illustrates another variation of the removable oral appliance inthe form of an appliance which is placed over an entire row of teeth inthe manner of a mouthguard.

FIG. 2C illustrates another variation of the removable oral appliancewhich is supported by an arch.

FIG. 2D illustrates another variation of an oral appliance configured asa mouthguard.

FIG. 3 illustrates a detail perspective view of the oral appliancepositioned upon the patient's teeth utilizable in combination with atransmitting assembly external to the mouth and wearable by the patientin another variation of the device.

FIG. 4 shows an illustrative configuration of one variation of theindividual components of the oral appliance device having an externaltransmitting assembly with a receiving and transducer assembly withinthe mouth.

FIG. 5 shows an illustrative configuration of another variation of thedevice in which the entire assembly is contained by the oral appliancewithin the user's mouth.

FIG. 6 illustrates an example of how multiple oral appliance hearing aidassemblies or transducers may be placed on multiple teeth throughout thepatient's mouth.

FIG. 7 illustrates another variation of a removable oral appliancesupported by an arch and having a microphone unit integrated within thearch.

FIG. 8A illustrates another variation of the removable oral appliancesupported by a connecting member which may be positioned along thelingual or buccal surfaces of a patient's row of teeth.

FIGS. 8B to 8E show examples of various cross-sections of the connectingsupport member of the appliance of FIG. 8A.

FIG. 9 shows yet another variation illustrating at least one microphoneand optionally additional microphone units positioned around the user'smouth and in wireless communication with the electronics and/ortransducer assembly.

FIG. 10 illustrates yet another example of a configuration forpositioning multiple transducers and/or processing units along apatient's dentition.

FIG. 11A illustrates another variation on the configuration forpositioning multiple transducers and/or processors supported via anarched connector.

FIG. 11B illustrates another variation on the configuration utilizing aconnecting member positioned along the lingual surfaces of a patient'sdentition.

FIG. 12A shows a configuration for positioning one or more transducerswith multiple microphones.

FIG. 12B schematically illustrates an example for integrating anacoustic echo cancellation system with the oral appliance.

FIG. 13A shows a configuration for positioning and utilizing multipleband transducers with the oral appliance.

FIG. 13B schematically illustrates another example for integratingmultiple band transducers with the oral appliance.

FIG. 14A shows a configuration for positioning multiple transducers foremulating directionality of audio signals perceived by a user.

FIG. 14B schematically illustrates an example for emulating thedirectionality of detected audio signals via multiple transducers.

FIG. 15 schematically illustrates an example for activating one or moretransducers to emulate directionality utilizing phase and/or amplitudemodified signals.

FIG. 16 schematically illustrates an example for optionally compensatingfor the relative positioning of the microphones with respect to the userfor emulating directionality of perceived audio signals.

FIG. 17A shows a configuration for positioning multiple transducerswhich may be configured to provide for one or more ancillaryauditory/conductance channels.

FIG. 17B schematically illustrates an example for providing one or moreancillary channels for secondary audio signals to be provided to a user.

FIG. 17C illustrates another variation where secondary device maydirectly transmit audio signals wirelessly via the oral appliance.

FIG. 18 schematically illustrates an example for optionally adjustingfeatures of the device such as the manner in which ancillary auditorysignals are transmitted to the user.

FIG. 19A illustrates one method for delivering ancillary audio signalsas vibrations transmitted in parallel.

FIG. 19B illustrates another method for delivering ancillary audiosignals as vibrations transmitted in series.

FIG. 19C illustrates yet another method for delivering ancillary audiosignals as vibrations transmitted in a hybrid form utilizing signalstransmitted in both parallel and series.

DETAILED DESCRIPTION OF THE INVENTION

An electronic and transducer device may be attached, adhered, orotherwise embedded into or upon a removable oral appliance or other oraldevice to form a hearing aid assembly. Such an oral appliance may be acustom-made device fabricated from a thermal forming process utilizing areplicate model of a dental structure obtained by conventional dentalimpression methods. The electronic and transducer assembly may receiveincoming sounds either directly or through a receiver to process andamplify the signals and transmit the processed sounds via a vibratingtransducer element coupled to a tooth or other bone structure, such asthe maxillary, mandibular, or palatine bone structure.

As shown in FIG. 1, a patient's mouth and dentition 10 is illustratedshowing one possible location for removably attaching hearing aidassembly 14 upon or against at least one tooth, such as a molar 12. Thepatient's tongue TG and palate PL are also illustrated for reference. Anelectronics and/or transducer assembly 16 may be attached, adhered, orotherwise embedded into or upon the assembly 14, as described below infurther detail.

FIG. 2A shows a perspective view of the patient's lower dentitionillustrating the hearing aid assembly 14 comprising a removable oralappliance 18 and the electronics and/or transducer assembly 16positioned along a side surface of the assembly 14. In this variation,oral appliance 18 may be fitted upon two molars 12 within tooth engagingchannel 20 defined by oral appliance 18 for stability upon the patient'steeth, although in other variations, a single molar or tooth may beutilized. Alternatively, more than two molars may be utilized for theoral appliance 18 to be attached upon or over. Moreover, electronicsand/or transducer assembly 16 is shown positioned upon a side surface oforal appliance 18 such that the assembly 16 is aligned along a buccalsurface of the tooth 12; however, other surfaces such as the lingualsurface of the tooth 12 and other positions may also be utilized. Thefigures are illustrative of variations and are not intended to belimiting; accordingly, other configurations and shapes for oralappliance 18 are intended to be included herein.

FIG. 2B shows another variation of a removable oral appliance in theform of an appliance 15 which is placed over an entire row of teeth inthe manner of a mouthguard. In this variation, appliance 15 may beconfigured to cover an entire bottom row of teeth or alternatively anentire upper row of teeth. In additional variations, rather thancovering the entire rows of teeth, a majority of the row of teeth may beinstead be covered by appliance 15. Assembly 16 may be positioned alongone or more portions of the oral appliance 15.

FIG. 2C shows yet another variation of an oral appliance 17 having anarched configuration. In this appliance, one or more tooth retainingportions 21, 23, which in this variation may be placed along the upperrow of teeth, may be supported by an arch 19 which may lie adjacent oralong the palate of the user. As shown, electronics and/or transducerassembly 16 may be positioned along one or more portions of the toothretaining portions 21, 23. Moreover, although the variation shownillustrates an arch 19 which may cover only a portion of the palate ofthe user, other variations may be configured to have an arch whichcovers the entire palate of the user.

FIG. 2D illustrates yet another variation of an oral appliance in theform of a mouthguard or retainer 25 which may be inserted and removedeasily from the user's mouth. Such a mouthguard or retainer 25 may beused in sports where conventional mouthguards are worn; however,mouthguard or retainer 25 having assembly 16 integrated therein may beutilized by persons, hearing impaired or otherwise, who may simply holdthe mouthguard or retainer 25 via grooves or channels 26 between theirteeth for receiving instructions remotely and communicating over adistance.

Generally, the volume of electronics and/or transducer assembly 16 maybe minimized so as to be unobtrusive and as comfortable to the user whenplaced in the mouth. Although the size may be varied, a volume ofassembly 16 may be less than 800 cubic millimeters. This volume is, ofcourse, illustrative and not limiting as size and volume of assembly 16and may be varied accordingly between different users.

Moreover, removable oral appliance 18 may be fabricated from variouspolymeric or a combination of polymeric and metallic materials using anynumber of methods, such as computer-aided machining processes usingcomputer numerical control (CNC) systems or three-dimensional printingprocesses, e.g., stereolithography apparatus (SLA), selective lasersintering (SLS), and/or other similar processes utilizingthree-dimensional geometry of the patient's dentition, which may beobtained via any number of techniques. Such techniques may include useof scanned dentition using intra-oral scanners such as laser, whitelight, ultrasound, mechanical three-dimensional touch scanners, magneticresonance imaging (MRI), computed tomography (CT), other opticalmethods, etc.

In forming the removable oral appliance 18, the appliance 18 may beoptionally formed such that it is molded to fit over the dentition andat least a portion of the adjacent gingival tissue to inhibit the entryof food, fluids, and other debris into the oral appliance 18 and betweenthe transducer assembly and tooth surface. Moreover, the greater surfacearea of the oral appliance 18 may facilitate the placement andconfiguration of the assembly 16 onto the appliance 18.

Additionally, the removable oral appliance 18 may be optionallyfabricated to have a shrinkage factor such that when placed onto thedentition, oral appliance 18 may be configured to securely grab onto thetooth or teeth as the appliance 18 may have a resulting size slightlysmaller than the scanned tooth or teeth upon which the appliance 18 wasformed. The fitting may result in a secure interference fit between theappliance 18 and underlying dentition.

In one variation, with assembly 14 positioned upon the teeth, as shownin FIG. 3, an extra-buccal transmitter assembly 22 located outside thepatient's mouth may be utilized to receive auditory signals forprocessing and transmission via a wireless signal 24 to the electronicsand/or transducer assembly 16 positioned within the patient's mouth,which may then process and transmit the processed auditory signals viavibratory conductance to the underlying tooth and consequently to thepatient's inner ear.

The transmitter assembly 22, as described in further detail below, maycontain a microphone assembly as well as a transmitter assembly and maybe configured in any number of shapes and forms worn by the user, suchas a watch, necklace, lapel, phone, belt-mounted device, etc.

FIG. 4 illustrates a schematic representation of one variation ofhearing aid assembly 14 utilizing an extra-buccal transmitter assembly22, which may generally comprise microphone or microphone array 30(referred to “microphone 30” for simplicity) for receiving sounds andwhich is electrically connected to processor 32 for processing theauditory signals. Processor 32 may be connected electrically totransmitter 34 for transmitting the processed signals to the electronicsand/or transducer assembly 16 disposed upon or adjacent to the user'steeth. The microphone 30 and processor 32 may be configured to detectand process auditory signals in any practicable range, but may beconfigured in one variation to detect auditory signals ranging from,e.g., 250 Hertz to 20,000 Hertz.

With respect to microphone 30, a variety of various microphone systemsmay be utilized. For instance, microphone 30 may be a digital, analog,and/or directional type microphone. Such various types of microphonesmay be interchangeably configured to be utilized with the assembly, ifso desired. Moreover, various configurations and methods for utilizingmultiple microphones within the user's mouth may also be utilized, asfurther described below.

Power supply 36 may be connected to each of the components intransmitter assembly 22 to provide power thereto. The transmittersignals 24 may be in any wireless form utilizing, e.g., radio frequency,ultrasound, microwave, Blue Tooth® (BLUETOOTH SIG, INC., Bellevue,Wash.), etc. for transmission to assembly 16. Assembly 22 may alsooptionally include one or more input controls 28 that a user maymanipulate to adjust various acoustic parameters of the electronicsand/or transducer assembly 16, such as acoustic focusing, volumecontrol, filtration, muting, frequency optimization, sound adjustments,and tone adjustments, etc.

The signals transmitted 24 by transmitter 34 may be received byelectronics and/or transducer assembly 16 via receiver 38, which may beconnected to an internal processor for additional processing of thereceived signals. The received signals may be communicated to transducer40, which may vibrate correspondingly against a surface of the tooth toconduct the vibratory signals through the tooth and bone andsubsequently to the middle ear to facilitate hearing of the user.Transducer 40 may be configured as any number of different vibratorymechanisms. For instance, in one variation, transducer 40 may be anelectromagnetically actuated transducer. In other variations, transducer40 may be in the form of a piezoelectric crystal having a range ofvibratory frequencies, e.g., between 250 to 4000 kHz.

Power supply 42 may also be included with assembly 16 to provide powerto the receiver, transducer, and/or processor, if also included.Although power supply 42 may be a simple battery, replaceable orpermanent, other variations may include a power supply 42 which ischarged by inductance via an external charger. Additionally, powersupply 42 may alternatively be charged via direct coupling to analternating current (AC) or direct current (DC) source. Other variationsmay include a power supply 42 which is charged via a mechanicalmechanism, such as an internal pendulum or slidable electricalinductance charger as known in the art, which is actuated via, e.g.,motions of the jaw and/or movement for translating the mechanical motioninto stored electrical energy for charging power supply 42.

In another variation of assembly 16, rather than utilizing anextra-buccal transmitter, hearing aid assembly 50 may be configured asan independent assembly contained entirely within the user's mouth, asshown in FIG. 5. Accordingly, assembly 50 may include at least oneinternal microphone 52 in communication with an on-board processor 54.Internal microphone 52 may comprise any number of different types ofmicrophones, as described below in further detail. At least oneprocessor 54 may be used to process any received auditory signals forfiltering and/or amplifying the signals and transmitting them totransducer 56, which is in vibratory contact against the tooth surface.Power supply 58, as described above, may also be included withinassembly 50 for providing power to each of the components of assembly 50as necessary.

In order to transmit the vibrations corresponding to the receivedauditory signals efficiently and with minimal loss to the tooth orteeth, secure mechanical contact between the transducer and the tooth isideally maintained to ensure efficient vibratory communication.Accordingly, any number of mechanisms may be utilized to maintain thisvibratory communication.

For any of the variations described above, they may be utilized as asingle device or in combination with any other variation herein, aspracticable, to achieve the desired hearing level in the user. Moreover,more than one oral appliance device and electronics and/or transducerassemblies may be utilized at any one time. For example, FIG. 6illustrates one example where multiple transducer assemblies 60, 62, 64,66 may be placed on multiple teeth. Although shown on the lower row ofteeth, multiple assemblies may alternatively be positioned and locatedalong the upper row of teeth or both rows as well. Moreover, each of theassemblies may be configured to transmit vibrations within a uniformfrequency range. Alternatively in other variations, different assembliesmay be configured to vibrate within overlapping or non-overlappingfrequency ranges between each assembly. As mentioned above, eachtransducer 60, 62, 64, 66 can be programmed or preset for a differentfrequency response such that each transducer may be optimized for adifferent frequency response and/or transmission to deliver a relativelyhigh-fidelity sound to the user.

Moreover, each of the different transducers 60, 62, 64, 66 can also beprogrammed to vibrate in a manner which indicates the directionality ofsound received by the microphone worn by the user. For example,different transducers positioned at different locations within theuser's mouth can vibrate in a specified manner by providing sound orvibrational queues to inform the user which direction a sound wasdetected relative to an orientation of the user, as described in furtherdetail below. For instance, a first transducer located, e.g., on auser's left tooth, can be programmed to vibrate for sound detectedoriginating from the user's left side. Similarly, a second transducerlocated, e.g., on a user's right tooth, can be programmed to vibrate forsound detected originating from the user's right side. Other variationsand queues may be utilized as these examples are intended to beillustrative of potential variations.

FIG. 7 illustrates another variation 70 which utilizes an arch 19connecting one or more tooth retaining portions 21, 23, as describedabove. However, in this variation, the microphone unit 74 may beintegrated within or upon the arch 19 separated from the transducerassembly 72. One or more wires 76 routed through arch 19 mayelectrically connect the microphone unit 74 to the assembly 72.Alternatively, rather than utilizing a wire 76, microphone unit 74 andassembly 72 may be wirelessly coupled to one another, as describedabove.

FIG. 8A shows another variation 80 which utilizes a connecting member 82which may be positioned along the lingual or buccal surfaces of apatient's row of teeth to connect one or more tooth retaining portions21, 23. Connecting member 82 may be fabricated from any number ofnon-toxic materials, such stainless steel, Nickel, Platinum, etc. andaffixed or secured 84, 86 to each respective retaining portions 21, 23.Moreover, connecting member 82 may be shaped to be as non-obtrusive tothe user as possible. Accordingly, connecting member 82 may beconfigured to have a relatively low-profile for placement directlyagainst the lingual or buccal teeth surfaces. The cross-sectional areaof connecting member 82 may be configured in any number of shapes solong as the resulting geometry is non-obtrusive to the user. FIG. 8Billustrates one variation of the cross-sectional area which may beconfigured as a square or rectangle 90. FIG. 8C illustrates anotherconnecting member geometry configured as a semi-circle 92 where the flatportion may be placed against the teeth surfaces. FIGS. 8D and 8Eillustrate other alternative shapes such as an elliptical shape 94 andcircular shape 96. These variations are intended to be illustrative andnot limiting as other shapes and geometries, as practicable, areintended to be included within this disclosure.

In yet another variation for separating the microphone from thetransducer assembly, FIG. 9 illustrates another variation where at leastone microphone 102 (or optionally any number of additional microphones104, 106) may be positioned within the mouth of the user whilephysically separated from the electronics and/or transducer assembly100. In this manner, the one or optionally more microphones 102, 104,106 may be wirelessly or by wire coupled to the electronics and/ortransducer assembly 100 in a manner which attenuates or eliminatesfeedback from the transducer, also described in further detail below.

In utilizing multiple transducers and/or processing units, severalfeatures may be incorporated with the oral appliance(s) to effect anynumber of enhancements to the quality of the conducted vibratory signalsand/or to emulate various perceptual features to the user to correlateauditory signals received by a user for transmitting these signals viasound conduction through teeth or bone structures in and/or around themouth.

As illustrated in FIG. 10, another variation for positioning one or moretransducers and/or processors is shown. In this instance generally, atleast two microphones may be positioned respectively along toothretaining portions 21, 23, e.g., outer microphone 110 positioned along abuccal surface of retaining portion 23 and inner microphone 112positioned along a lingual surface of retaining portion 21. The one ormore microphones 110, 112 may receive the auditory signals which areprocessed and ultimately transmitted through sound conductance via oneor more transducers 114, 116, 118, one or more of which may be tuned toactuate only along certain discrete frequencies, as described in furtherdetail below.

Moreover, the one or more transducers 114, 116, 118 may be positionedalong respective retaining portions 21, 23 and configured to emulatedirectionality of audio signals received by the user to provide a senseof direction with respect to conducted audio signals. Additionally, oneor more processors 120, 124 may also be provided along one or bothretaining portions 21, 23 to process received audio signals, e.g., totranslate the audio signals into vibrations suitable for conduction tothe user, as well as other providing for other functional features.Furthermore, an optional processor 122 may also be provided along one orboth retaining portions 21, 23 for interfacing and/or receiving wirelesssignals from other external devices such as an input control, asdescribed above, or other wireless devices.

FIG. 11A illustrates another configuration utilizing an arch 130 similarto the configuration shown in FIG. 7 for connecting the multipletransducers and processors positioned along tooth retaining portions 21,23. FIG. 11B illustrates yet another configuration utilizing aconnecting member 132 positioned against the lingual surfaces of theuser's teeth, similar to the configuration shown in FIG. 8A, also forconnecting the multiple transducers and processors positioned alongtooth retaining portions 21, 23.

In configurations particularly where the one or more microphones arepositioned within the user's mouth, filtering features such as AcousticEcho Cancellation (AEC) may be optionally utilized to eliminate ormitigate undesired sounds received by the microphones. AEC algorithmsare well utilized and are typically used to anticipate the signal whichmay re-enter the transmission path from the microphone and cancel it outby digitally sampling an initial received signal to form a referencesignal. Generally, the received signal is produced by the transducer andany reverberant signal which may be picked up again by the microphone isagain digitally sampled to form an echo signal. The reference and echosignals may be compared such that the two signals are summed ideally at180° out of phase to result in a null signal, thereby cancelling theecho.

In the variation shown in FIG. 12A, at least two intra-buccalmicrophones 110, 112 may be utilized to separate out desired sounds(e.g., sounds received from outside the body such as speech, music,etc.) from undesirable sounds (e.g., sounds resulting from chewing,swallowing, breathing, self-speech, teeth grinding, etc.). If theseundesirable sounds are not filtered or cancelled, they may be amplifiedalong with the desired audio signals making for potentiallyunintelligible audio quality for the user. Additionally, desired audiosounds may be generally received at relatively lower sound pressurelevels because such signals are more likely to be generated at adistance from the user and may have to pass through the cheek of theuser while the undesired sounds are more likely to be generated locallywithin the oral cavity of the user.

Samples of the undesired sounds may be compared against desired soundsto eliminate or mitigate the undesired sounds prior to actuating the oneor more transducers to vibrate only the resulting desired sounds to theuser. In this example, first microphone 110 may be positioned along abuccal surface of the retaining portion 23 to receive desired soundswhile second microphone 112 may be positioned along a lingual surface ofretaining portion 21 to receive the undesirable sound signals. Processor120 may be positioned along either retaining portion 21 or 23, in thiscase along a lingual surface of retaining portion 21, and may be inwired or wireless communication with the microphones 110, 112.

Although audio signals may be attenuated by passing through the cheek ofthe user, especially when the mouth is closed, first microphone 110 maystill receive the desired audio signals for processing by processor 120,which may also amplify the received audio signals. As illustratedschematically in FIG. 12B, audio signals for desired sounds, representedby far end speech 140, are shown as being received by first microphone110. Audio signals for the undesired sounds 152, represented by near endspeech 150, are shown as being received by second microphone 112.Although it may be desirable to position the microphones 110, 112 intheir respective positions to optimize detection of their respectivedesirable and undesirable sounds, they may of course be positioned atother locations within the oral cavity as so desired or practicable.Moreover, while it may also be desirable for first and second microphone110, 112 to detect only their respective audio signals, this is notrequired. However, having the microphones 110, 112 detect differentversions of the combination of desired and undesired sounds 140, 150,respectively, may be desirable so as to effectively process thesesignals via AEC processor 120.

The desired audio signals may be transmitted via wired or wirelesscommunication along a receive path 142 where the signal 144 may besampled and received by AEC processor 120. A portion of the far endspeech 140 may be transmitted to one or more transducers 114 where itmay initially conduct the desired audio signals via vibration 146through the user's bones. Any resulting echo or reverberations 148 fromthe transmitted vibration 146 may be detected by second microphone 112along with any other undesirable noises or audio signals 150, asmentioned above. The undesired signals 148, 150 detected by secondmicrophone 112 or the sampled signal 144 received by AEC processor 120may be processed and shifted out of phase, e.g., ideally 180° out ofphase, such that the summation 154 of the two signals results in acancellation of any echo 148 and/or other undesired sounds 150.

The resulting summed audio signal may be redirected through an adaptivefilter 156 and re-summed 154 to further clarify the audio signal untilthe desired audio signals is passed along to the one or more transducers114 where the filtered signal 162, free or relatively free from theundesired sounds, may be conducted 160 to the user. Although twomicrophones 110, 112 are described in this example, an array ofadditional microphones may be utilized throughout the oral cavity of theuser. Alternatively, as mentioned above, one or more microphones mayalso be positioned or worn by the user outside the mouth, such as in abracelet, necklace, etc. and used alone or in combination with the oneor more intra-buccal microphones. Furthermore, although threetransducers 114, 116, 118 are illustrated, other variations may utilizea single transducer or more than three transducers positioned throughoutthe user's oral cavity, if so desired.

Independent from or in combination with acoustic echo cancellation,another processing feature for the oral appliance may include use of amultiband actuation system to facilitate the efficiency with which audiosignals may be conducted to the user. Rather than utilizing a singletransducer to cover the entire range of the frequency spectrum (e.g.,200 Hz to 10,000 Hz), one variation may utilize two or more transducerswhere each transducer is utilized to deliver sounds within certainfrequencies. For instance, a first transducer may be utilized to deliversounds in the 200 Hz to 2000 Hz frequency range and a second transducermay be used to deliver sounds in the 2000 Hz to 10,000 Hz frequencyrange. Alternatively, these frequency ranges may be discrete oroverlapping. As individual transducers may be configured to handle onlya subset of the frequency spectrum, the transducers may be moreefficient in their design.

Additionally, for certain applications where high fidelity signals arenot necessary to be transmitted to the user, individual higher frequencytransducers may be shut off to conserve power. In yet anotheralternative, certain transducers may be omitted, particularlytransducers configured for lower frequency vibrations.

As illustrated in FIG. 13A, a configuration for utilizing multipletransducers is shown where individual transducers may be attuned totransmit only within certain frequency ranges. For instance, transducer116 may be configured to transmit audio signals within the frequencyrange from, e.g., 200 Hz to 2000 Hz, while transducers 114 and/or 118may be configured to transmit audio signals within the frequency rangefrom, e.g., 2000 Hz to 10,000 Hz. Although the three transducers areshown, this is intended to be illustrative and fewer than three or morethan three transducers may be utilized in other variations. Moreover,the audible frequency ranges are described for illustrative purposes andthe frequency range may be sub-divided in any number of sub-rangescorrelating to any number of transducers, as practicable. The choice ofthe number of sub-ranges and the lower and upper limits of eachsub-range may also be varied depending upon a number of factors, e.g.,the desired fidelity levels, power consumption of the transducers, etc.

One or both processors 120 and/or 124, which are in communication withthe one or more transducers (in this example transducers 114, 116, 118),may be programmed to treat the audio signals for each particularfrequency range similarly or differently. For instance, processors 120and/or 124 may apply a higher gain level to the signals from one bandwith respect to another band. Additionally, one or more of thetransducers 114, 116, 118 may be configured differently to optimallytransmit vibrations within their respective frequency ranges. In onevariation, one or more of the transducers 114, 116, 118 may be varied insize or in shape to effectuate an optimal configuration for transmissionwithin their respective frequencies.

As mentioned above, the one or more of transducers 114, 116, 118 mayalso be powered on or off by the processor to save on power consumptionin certain listening applications. As an example, higher frequencytransducers 114, 118 may be shut off when higher frequency signals arenot utilized such as when the user is driving. In other examples, theuser may activate all transducers 114, 116, 118 such as when the user islistening to music. In yet another variation, higher frequencytransducers 114, 118 may also be configured to deliver high volume audiosignals, such as for alarms, compared to lower frequency transducers116. Thus, the perception of a louder sound may be achieved just byactuation of the higher frequency transducers 114, 118 without having toactuate any lower frequency transducers 116.

An example of how audio signals received by a user may be split intosub-frequency ranges for actuation by corresponding lower or higherfrequency transducers is schematically illustrated in FIG. 13B. In thisexample, an audio signal 170 received by the user via microphones 110and/or 112 may be transmitted 172 to one or more processors 120 and/or124. Once the audio signals have been received by the respectiveprocessor, the signal may be filtered by two or more respective filtersto transmit frequencies within specified bands. For instance, firstfilter 174 may receive the audio signal 172 and filter out the frequencyspectrum such that only the frequency range between, e.g., 200 Hz to2000 Hz, is transmitted 178. Second filter 176 may also receive theaudio signal 172 and filter out the frequency spectrum such that onlythe frequency range between, e.g., 2000 Hz to 10,000 Hz, is transmitted180.

Each respective filtered signal 178, 180 may be passed on to arespective processor 182, 184 to further process each band's signalaccording to an algorithm to achieve any desired output per transducer.Thus, processor 182 may process the signal 178 to create the outputsignal 194 to vibrate the lower frequency transducer 116 accordinglywhile the processor 184 may process the signal 180 to create the outputsignal 196 to vibrate the higher frequency transducers 114 and/or 118accordingly. An optional controller 186 may receive control data 188from user input controls, as described above, for optionally sendingsignals 190, 192 to respective processors 182, 184 to shut on/off eachrespective processor and/or to append ancillary data and/or controlinformation to the subsequent transducers.

In addition to or independent from either acoustic echo cancellationand/or multiband actuation of transducers, yet another process which mayutilize the multiple transducers may include the utilization ofdirectionality via the conducted vibrations to emulate the directionalperception of audio signals received by the user. Generally, humanhearing is able to distinguish the direction of a sound wave byperceiving differences in sound pressure levels between the two cochlea.In one example for providing the perception of directionality with anoral appliance, two or more transducers, such as transducers 114, 118,may be positioned apart from one another along respective retainingportions 21, 23, as shown in FIG. 14A.

One transducer may be actuated corresponding to an audio signal whilethe other transducer is actuated corresponding to the same audio signalbut with a phase and/or amplitude and/or delay difference intentionallyinduced corresponding to a direction emulated for the user. Generally,upon receiving a directional audio signal and depending upon thedirection to be emulated and the separation between the respectivetransducers, a particular phase and/or gain and/or delay change to theaudio signal may be applied to the respective transducer while leavingthe other transducer to receive the audio signal unchanged.

As illustrated in the schematic illustration of FIG. 14B, audio signalsreceived by the one or more microphones 110, 112, which may include anarray of intra-buccal and/or extra-buccal microphones as describedabove, may be transmitted wirelessly or via wire to the one or moreprocessors 120, 124, as above. The detected audio signals may beprocessed to estimate the direction of arrival of the detected sound 200by applying any number of algorithms as known in the art. The processormay also simply reproduce a signal that carries the information of thereceived sound 202 detected from the microphones 110, 112. This mayentail a transfer of the information from one of the microphones, a sumof the signals received from the microphones, or a weighted sum of thesignals received from the microphones, etc., as known in the art.Alternatively, the reproduced sound 202 may simply pass the informationin the audio signals from any combination of the microphones or from anysingle one of the microphones, e.g., a first microphone, a lastmicrophone, a random microphone, a microphone with the strongestdetected audio signals, etc.

With the estimated direction of arrival of the detected sound 200determined, the data may be modified for phase and/or amplitude and/ordelay adjustments 204 as well as for orientation compensation 208, ifnecessary, based on additional information received the microphones 110,112 and relative orientation of the transducers 114, 116, 118, asdescribed in further detail below. The process of adjusting for phaseand/or amplitude and/or delay 204 may involve calculating one phaseadjustment for one of the transducers. This may simply involve analgorithm where given a desired direction to be emulated, a table ofvalues may correlate a set of given phase and/or amplitude and/or delayvalues for adjusting one or more of the transducers. Because theadjustment values may depend on several different factors, e.g., speedof sound conductance through a user's skull, distance betweentransducers, etc., each particular user may have a specific table ofvalues. Alternatively, standard set values may be determined for groupsof users having similar anatomical features, such as jaw size amongother variations, and requirements. In other variations, rather thanutilizing a table of values in adjusting for phase and/or amplitudeand/or delay 204, set formulas or algorithms may be programmed inprocessor 120 and/or 124 to determine phase and/or amplitude and/ordelay adjustment values. Use of an algorithm could simply utilizecontinuous calculations in determining any adjustment which may beneeded or desired whereas the use of a table of values may simplyutilize storage in memory.

Once any adjustments in phase and/or amplitude and/or delay 204 aredetermined and with the reproduced signals 202 processed from themicrophones 110, 112, these signals may then be processed to calculateany final phase and/or amplitude and/or delay adjustments 206 and thesefinal signals may be applied to the transducers 114, 116, 118, asillustrated, to emulate the directionality of received audio signals tothe user. A detailed schematic illustration of the final phase and/oramplitude and/or delay adjustments 206 is illustrated in FIG. 15 wherethe signals received from 202 may be split into two or more identicalsignals 214, 216 which may correlate to the number of transducersutilized to emulate the directionality. The phase and/or amplitudeand/or delay adjustments 204 may be applied to one or more of thereceived signals 214, 216 by applying either a phase adjustment (Φ) 210,e.g., any phase adjustment from 0° to 360°, and/or amplitude adjustment(α) 212, e.g., any amplitude adjustment from 1.0 to 0.7, and/or delay(τ) 213, e.g., any time delay of 0 to 125 μ-sec, to result in at leastone signal 218 which has been adjusted for transmission via the one ormore transducers. These values are presented for illustrative purposesand are not intended to be limiting. Although the adjustments may beapplied to both signals 214, 216, they may also be applied to a singlesignal 214 while one of the received signals 216 may be unmodified andpassed directly to one of the transducers.

As mentioned above, compensating 208 for an orientation of thetransducers relative to one another as well as relative to anorientation of the user may be taken into account in calculating anyadjustments to phase and/or amplitude and/or delay of the signalsapplied to the transducers. For example, the direction 230 perpendicularto a line 224 connecting the microphones 226, 228 (intra-buccal and/orextra-buccal) may define a zero degree direction of the microphones. Azero degree direction of the user's head may be indicated by thedirection 222, which may be illustrated as in FIG. 16 as the directionthe user's nose points towards. The difference between the zero degreedirection of the microphones and the zero degree direction of the user'shead may define an angle, Θ, which may be taken into account as acorrection factor when determining the phase and/or amplitudeadjustments. Accordingly, if the positioning of microphones 226, 228 aresuch that their zero degree direction is aligned with the zero degreedirection of the user's head, then little or no correction may benecessary. If the positioning of the microphones 226, 228 is alteredrelative to the user's body and an angle is formed relative to the zerodegree direction of the user's head, then the audio signals received bythe user and the resulting vibrations conducted by the transducers tothe user may be adjusted for phase and/or amplitude taking into accountthe angle, Θ, when emulating directionality with the vibratingtransducers.

In addition to or independent from any of the processes described above,another feature which may utilize the oral appliance and processingcapabilities may include the ability to vibrationally conduct ancillaryaudio signals to the user, e.g., the oral appliance may be configured towirelessly receive and conduct signals from secondary audio sources tothe user. Examples may include the transmission of an alarm signal whichonly the user may hear or music conducted to the user in publiclocations, etc. The user may thus enjoy privacy in receiving theseancillary signals while also being able to listen and/or converse in anenvironment where a primary audio signal is desired.

FIG. 17A shows an example of placing one or more microphones 110, 112 aswell as an optional wireless receiver 122 along one or both retainingportions 21, 23, as above. In a schematic illustration shown in FIG.17B, one variation for receiving and processing multiple audio signalsis shown where various audio sources 234, 238 (e.g., alarms, musicplayers, cell phones, PDA's, etc.) may transmit their respective audiosignals 236, 240 to an audio receiver processor 230, which may receivethe sounds via the one or more microphones and process them for receiptby an audio application processor 232, which may apply the combinedsignal received from audio receiver processor 230 and apply them to oneor more transducers to the user 242. FIG. 17C illustrates anothervariation where a wireless receiver and/or processor 122 located alongone or more of the retaining portions 21 may be configured to wirelesslyreceive audio signals from multiple electronic audio sources 244. Thisfeature may be utilized with any of the variations described hereinalone or in combination.

The audio receiver processor 230 may communicate wirelessly or via wirewith the audio application processor 232. During one example of use, aprimary audio signal 240 (e.g., conversational speech) along with one ormore ancillary audio signals 236 (e.g., alarms, music players, cellphones, PDA's, etc.) may be received by the one or more microphones of areceiver unit 250 of audio receiver processor 230. The primary signal250 and ancillary signals 254 may be transmitted electrically to amultiplexer 256 which may combine the various signals 252, 254 in viewof optional methods, controls and/or priority data 262 received from auser control 264, as described above. Parameters such as prioritizationof the signals as well as volume, timers, etc., may be set by the usercontrol 264. The multiplexed signal 258 having the combined audiosignals may then be transmitted to processor 260, which may transmit themultiplexed signal 266 to the audio application processor 232, asillustrated in FIG. 18.

As described above, the various audio signals 236, 240 may be combinedand multiplexed in various forms 258 for transmission to the user 242.For example, one variation for multiplexing the audio signals viamultiplexer 256 may entail combining the audio signals such that theprimary 240 and ancillary 236 signals are transmitted by the transducersin parallel where all audio signals are conducted concurrently to theuser, as illustrated in FIG. 19A, which graphically illustratestransmission of a primary signal 270 in parallel with the one or moreancillary signals 272, 272 over time, T. The transmitted primary signal270 may be transmitted at a higher volume, i.e., a higher dB level, thanthe other ancillary signals 272, 274, although this may be varieddepending upon the user preferences.

Alternatively, the multiplexed signal 258 may be transmitted such thatthe primary 240 and ancillary 236 signals are transmitted in series, asgraphically illustrated in FIG. 19B. In this variation, the transmittedprimary 270 and ancillary 272, 274 signals may be conducted to the userin a pre-assigned, random, preemptive, or non-preemptive manner whereeach signal is conducted serially.

In yet another example, the transmitted signals may be conducted to theuser in a hybrid form combining the parallel and serial methodsdescribed above and as graphically illustrated in FIG. 19C. Depending onuser settings or preferences, certain audio signals 274, e.g., emergencyalarms, may preempt primary 270 and/or ancillary 272 signals from othersources at preset times 276 or intermittently or in any other mannersuch that the preemptive signal 274 is played such that it is the onlysignal played back to the user.

The applications of the devices and methods discussed above are notlimited to the treatment of hearing loss but may include any number offurther treatment applications. Moreover, such devices and methods maybe applied to other treatment sites within the body. Modification of theabove-described assemblies and methods for carrying out the invention,combinations between different variations as practicable, and variationsof aspects of the invention that are obvious to those of skill in theart are intended to be within the scope of the claims.

1. A method of transmitting an audio signal through bone, comprising:positioning a housing in a mouth of a user such that a first transduceris positioned in communication with a first tooth surface and a secondtransducer is positioned in communication with a second tooth surface;receiving an audio signal via at least a first microphone; filtering theaudio signal into at least a first frequency range and a secondfrequency range; vibrating the first transducer to transmit the firstfrequency range through the first tooth surface; and vibrating thesecond transducer to transmit the second frequency range through thesecond tooth surface, wherein the first or second transducer isselectively powered on or off depending on a quality of the audio signalto be transmitted to the user.
 2. The method of claim 1 whereinreceiving comprises receiving the audio signal via the first microphonepositioned intra-buccal to the user.
 3. The method of claim 1 whereinfiltering comprises filtering the first and second frequency ranges suchthat each range overlaps with respect to one another.
 4. The method ofclaim 1 wherein filtering comprises filtering the first and secondfrequency ranges such that each range is separate from one another. 5.The method of claim 1 wherein filtering comprises filtering the audiosignal by two or more filters.
 6. The method of claim 1 whereinfiltering comprises filtering the first frequency range to have a lowerrelative frequency range compared to the second frequency range having ahigher relative frequency.
 7. The method of claim 1 wherein filteringcomprises filtering the audio signal such that the first frequency rangeis from 200 Hz to 2000 Hz.
 8. The method of claim 7 wherein filteringcomprises filtering the audio signal such that the second frequencyrange is from 2000 Hz to 10,000 Hz.
 9. The method of claim 1 whereinfiltering comprises altering the first and/or second frequency ranges.10. The method of claim 1 wherein the first and second transducer areselectively powered on or off depending on a quality of the audio signalto be transmitted to the user.
 11. A method of transmitting an audiosignal through bone, comprising: positioning a housing onto at least onetooth of a user such that a first transducer is positioned incommunication with the at least one tooth and a second transducer ispositioned in communication with the at least one tooth: receiving anaudio signal via at least a first microphone; filtering the audio signalinto at least a first frequency range and a second frequency range;vibrating the first transducer to transmit the first frequency rangethrough the at least one tooth; and vibrating the second transducer totransmit the second frequency range through the at least one tooth,wherein the first or second transducer is selectively powered on and offdepending on a quality of the audio signal to be transmitted to theuser.
 12. The method of claim 11 wherein receiving comprises receivingthe audio signal via the first microphone positioned intra-buccal to theuser.
 13. The method of claim 11 wherein filtering comprises filteringthe first and second frequency ranges such that each range overlaps withrespect to one another.
 14. The method of claim 11 wherein filteringcomprises filtering the first and second frequency ranges such that eachrange is separate from one another.
 15. The method of claim 11 whereinfiltering comprises filtering the audio signal by two or more filters.16. The method of claim 11 wherein filtering comprises filtering thefirst frequency range to have a lower relative frequency range comparedto the second frequency range having a higher relative frequency. 17.The method of claim 11 wherein filtering comprises filtering the audiosignal such that the first frequency range is from 200 Hz to 2000 Hz.18. The method of claim 17 wherein filtering comprises filtering theaudio signal such that the second frequency range is from 2000 Hz to10,000 Hz.
 19. The method of claim 11 wherein filtering comprisesaltering the first and/or second frequency ranges.
 20. A method oftransmitting an audio signal through bone, comprising: providing anapparatus comprising a housing and a transducer disposed within or uponthe housing, wherein the housing is biased to press against at least onetooth of the user to secure the apparatus to the at least one tooth;positioning the housing onto the at least one tooth of a user; receivingan audio signal via a microphone positioned; filtering the audio signal;and vibrating the transducer against the at least one tooth of the userto transmit the audio signal in the frequency range into the at leastone tooth and through the bone of the user.